Plant Respiration Not Just An Evolutionary Leftover, Study Shows

Date:

July 26, 2004

Source:

University Of California - Davis

Summary:

A biological process in plants, thought to be useless and even wasteful, has significant benefits and should not be engineered out -- particularly in the face of looming climate change, says a team of UC Davis researchers.

Share:

Total shares:

FULL STORY

A biological process in plants, thought to be useless and even wasteful, has significant benefits and should not be engineered out -- particularly in the face of looming climate change, says a team of UC Davis researchers.

The researchers have found that the process, photorespiration, is necessary for healthy plant growth and if impaired could inhibit plant growth, particularly as atmospheric carbon dioxide rises as it is globally. Their findings are published this week in the Proceedings of the National Academy of Sciences.

Over the past two hundred years, scientists have come to understand that plants are amazing biochemical factories that harness energy from sunlight to convert water and carbon dioxide into sugars that fuel the plant, while giving off oxygen.

Though elegantly simple in concept, this process, known as photosynthesis, is remarkably complex in detail. And for years, researchers have been puzzled by another process, photorespiration, which seems to have annoyingly associated with photosynthesis down the evolutionary pathway.

Photorespiration has appeared to be downright wasteful because it virtually undoes much of the work of photosynthesis by converting sugars in the plant back into carbon dioxide, water and energy.

Believing that photorespiration is a consequence of the higher levels of atmospheric carbon dioxide in long past ages, many scientists concluded that photorespiration is no longer necessary. Some have even set about to genetically engineer crop plants so that the activity of the enzyme that initiates both the light-independent reactions of photosynthesis and photorespiration would favor photosynthesis to a greater extent and minimize photorespiration.

The result, they have thought, would be more productive crop plants that make more efficient use of available resources.

But the new UC Davis study suggests that there is more to photorespiration than meets the eye and any attempts to minimize its activity in crop plants would be ill advised.

"Photorespiration is a mysterious process that under present condition dissipates about 25 percent of the energy that a plant captures during photosynthesis," said Arnold Bloom, a professor in UC Davis' vegetable crops department and lead researcher on the study. "But our research has shown that photorespiration enables the plant to take inorganic nitrogen in the form of nitrate and convert it into a form that is useful for plant growth."

The UC Davis team used two different methods to demonstrate in both wheat and Arabidopsis, a common research plant, that when plants are exposed to elevated levels of atmospheric carbon dioxide or low levels of oxygen -- both conditions that inhibit photorespiration -- nitrate assimilation in the plant's shoot slows down. Eventually, a shortage of nitrogen will curtail the plant's growth.

"This explains why many plants are unable to sustain rapid growth when there is a significant increase in atmospheric carbon dioxide," said Bloom. "And, as we anticipate a doubling of atmospheric carbon dioxide associated with global climate change by the end of this century, our results suggest that it would not be wise to decrease photorespiration in crop plants."

The UC Davis study was supported by the National Science Foundation, the U.S. Department of Agriculture and an Israel Binational Agricultural Research and Development Fund fellowship.

University Of California - Davis. "Plant Respiration Not Just An Evolutionary Leftover, Study Shows." ScienceDaily. ScienceDaily, 26 July 2004. <www.sciencedaily.com/releases/2004/07/040723093305.htm>.

University Of California - Davis. (2004, July 26). Plant Respiration Not Just An Evolutionary Leftover, Study Shows. ScienceDaily. Retrieved August 2, 2015 from www.sciencedaily.com/releases/2004/07/040723093305.htm

University Of California - Davis. "Plant Respiration Not Just An Evolutionary Leftover, Study Shows." ScienceDaily. www.sciencedaily.com/releases/2004/07/040723093305.htm (accessed August 2, 2015).

July 31, 2015  Resettlement projects in the Amazon are driving severe tropical deforestation, according to new research. Widely hailed as a socially responsible and 'innocuous' strategy of land redistribution, ... read more

July 29, 2015  Viewing aquarium displays led to noticeable reductions in blood pressure and heart rate, a research team found in the first study of its kind. They also noted that higher numbers of fish helped to ... read more

July 31, 2015  A new study examines how consuming the concentrated extract of thylakoids found in spinach can reduce hunger and cravings. Thylakoids encourage the release of satiety hormones, which is very ... read more

July 30, 2015  The behavior of fruit flies, which are commonly used in laboratory experiments, is altered by electric fields, new research shows. The research indicates that the wings of the insects are disturbed ... read more

July 31, 2015  Starvation early in life can alter an organism for generations to come, according to a new study in nematodes. The epigenetic effects are a 'bet-hedging strategy.' Famine survivors are smaller and ... read more

July 31, 2015  The humble butterfly could hold the key to unlocking new techniques to make solar energy cheaper and more efficient, pioneering new research has shown. By mimicking the v-shaped posture adopted by ... read more

July 20, 2014  The size and age of plants has more of an impact on their productivity than temperature and precipitation, according to a landmark study. They show that variation in terrestrial ecosystems is ... read more

Nov. 6, 2011  Whether a species can evolve to survive climate change may depend on the biodiversity of its ecological community, according to a new mathematical model that simulates the effect of climate change on ... read more

Mar. 16, 2011  The phenotypic plasticity of plants, which enables them to change their structure and function, helps them to adapt to environmental change, according to new research. This research will make it ... read more